You need images all the time--for newsletters, worship slides, event advertisements, websites, messages of all sorts. More, you need legal images. Fortunately, there are a number of good sources for such images. I am sticking to free sources here. Any suggestions for further additions or amendments are welcome.
Pixabay offers a massive library of free images with no restrictions attached. They are highly searchable by all sorts of concept and concrete keywords--anything from "men" to "glory." The primary drawback is that the images of people are heavily white; it is easy to imply, for example, that only white people pray if one isn't careful with the images.
Unsplash is also a great source and the images of people are more varied. Their keywording is also robust, so concept and action words usually provide a good range of choices.
Nappy.co offers "Beautiful, high-res photos of black and brown people for free." They seem to have a good selection, but are so far not as well key-worded. A search for "women" will turn up plenty; a search for "joy" or "prayer" will get scant results. Hopefully that will improve!
The Metropolitan Museum of Art 0ffers a number of free works. These ttend to be much older--often Medieval and/or black and white. Be sure to check "Creative Commons" when you search as not all of the images on the site are free for use.